============================================ WARNING: possible recursive locking detected 5.15.164-syzkaller #0 Not tainted -------------------------------------------- syz.2.421/9040 is trying to acquire lock: ffff0000d5be2398 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000d5be2398 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff0000d5be2398 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 but task is already holding lock: ffff0000e336b898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000e336b898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff0000e336b898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** May be due to missing lock nesting notation 12 locks held by syz.2.421/9040: #0: ffff800014c91660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #1: ffff800014c916c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #2: ffff800014c916c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #3: ffff0000c1867258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #3: ffff0000c1867258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin+0x130/0x2bc include/net/sch_generic.h:173 #4: ffff0000e336b898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #4: ffff0000e336b898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] #4: ffff0000e336b898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 #5: ffff0000e05824e0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #5: ffff0000e05824e0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0x100/0x188 net/ipv6/icmp.c:118 #6: ffff800014c91660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #7: ffff800014c916c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #8: ffff800014c91660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #9: ffff800014c916c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #10: ffff800014c916c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #11: ffff0000ec88e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #11: ffff0000ec88e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin+0x130/0x2bc include/net/sch_generic.h:173 stack backtrace: CPU: 1 PID: 9040 Comm: syz.2.421 Not tainted 5.15.164-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 __lock_acquire+0x62bc/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __netif_tx_lock include/linux/netdevice.h:4429 [inline] sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3844 [inline] __dev_queue_xmit+0x14b4/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_hh_output include/net/neighbour.h:493 [inline] neigh_output include/net/neighbour.h:507 [inline] ip6_finish_output2+0x1314/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbf8/0x1788 net/ipv6/ndisc.c:509 ndisc_send_ns+0x538/0x6ec net/ipv6/ndisc.c:651 ndisc_solicit+0x2f4/0x47c neigh_probe+0xc4/0x138 net/core/neighbour.c:1017 __neigh_event_send+0xca4/0x1338 net/core/neighbour.c:1178 neigh_event_send include/net/neighbour.h:438 [inline] neigh_resolve_output+0x178/0x5dc net/core/neighbour.c:1488 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161 ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1943 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:1963 icmpv6_push_pending_frames+0x244/0x398 net/ipv6/icmp.c:311 icmp6_send+0x11a4/0x1b18 net/ipv6/icmp.c:630 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x44/0x4a8 net/ipv6/route.c:2794 dst_link_failure+0x11c/0x160 include/net/dst.h:422 ip_tunnel_xmit+0x16e0/0x2334 net/ipv4/ip_tunnel.c:843 __gre_xmit net/ipv4/ip_gre.c:474 [inline] erspan_xmit+0x9cc/0x14cc net/ipv4/ip_gre.c:723 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3633 sch_direct_xmit+0x2e0/0x484 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3844 [inline] __dev_queue_xmit+0x14b4/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_resolve_output+0x52c/0x5dc net/core/neighbour.c:1504 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] rawv6_send_hdrinc+0xd64/0x1c14 net/ipv6/raw.c:691 rawv6_sendmsg+0x1074/0x1bcc net/ipv6/raw.c:949 inet_sendmsg+0x15c/0x290 net/ipv4/af_inet.c:836 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] sock_write_iter+0x2b0/0x3f8 net/socket.c:1079 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x884/0xb44 fs/read_write.c:594 ksys_write+0x15c/0x26c fs/read_write.c:647 __do_sys_write fs/read_write.c:659 [inline] __se_sys_write fs/read_write.c:656 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:656 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584